The present invention relates to a novel Serratia marcescens strain, a prodigiosin, and the use of the prodigiosin in immunosuppression fields. More particularly, the present invention relates to a novel Serratia marcescens strain which can produce the prodigiosin, and the use of the prodigiosin as an immunosuppressive.
Over the recent few years, active study and research have been and continued to be directed to the development of immunosuppressives, which are useful for the study on immunocytes and immune responses and for the treatment of the diseases requiring immunosuppression. For instance, immunosuppressives are utilized in researching almost all of immune responses, including cytokine production, T-cell activation, antibody production, cell death, DNA synthesis, immunocyte differentiation, intracellular signal transduction, etc. The immunosuppressives are also used to treat the diseases attributable to exaggerated immune responses, such as hypersensitive immune response and allergies. In addition, they are needed to suppress excess immune responses upon transplantation of organs, such as the kidney, the liver, the pancreas, marrow, the heart, skin, the lung, etc.
Prevailing immunosuppressives include, for example, cyclosporin A, cyclophosphamide, rapamycin, FK-506, etc. Many immunosuppressives which show similar or different suppressing behaviors are now under research.
The microorganisms belonging to genus Streptomyces or Serratia produce red substances of pyrrolylpyromethene structures, examples of which include prodigiosin, metacycloprodigiocin, prodigiosene, methoxyprodigiosin, and prodigiosin 25-C. They are now known to be of antibacterial and antimalarial activity and, particularly, prodigiosin 25-C shows an immunosuppressing effect.
It is an object of the present invention to provide a novel strain Serratia marcescens which produce a prodigiosin.
It is another object of the present invention to provide a prodigiosin as an immunosuppressive.
The detailed description of the present invention will follow isolation of a desired microorganism strain; mycological characterization of the strain; extraction of prodigiosin with organic solvent; purification of prodigiosin through silica gel column and thin layer chromatography; structure analysis through nuclear magnetic resonance; utility of the prodigiosin as an immunosuppressive.
Germ-free test animals, mice BDF1 and B6C3F1, obtained from Genetic Resources Center, Korean Research Institute of Bioscience and Biotechnology in the Korean Institute of Science and Technology, were used for the assay of the immunosuppressive activity of prodigiosin. The data from the ex vivo experiments concerning the immunosuppressive effect of prodigiosin show that as much as 300 nM of prodigiosin has a cytotoxic effect, but no effects at less than 100 nM. At such concentrations as show no cytotoxic effects, prodigiosin cannot suppress the immune response of B lymphocytes. Prodigiosin had no influence on the antibody production and proliferation of B lymphocytes, but has a potential suppressive effect on the proliferation and activity of T lymphocytes. This selective immunosuppression for T lymphocytes is not ascribed to the selective cytotoxicity for T lymphocytes. The same immunosuppression results as in the ex vivo experiments were obtained in in vivo experiments. When T lymphocyte activity was measured by use of a graft versus host reaction and a T cell-dependent antibody producing reaction, the prodigiosin suppressed the immune response, but exerted no toxicity on animals. Therefore, the immunosuppressive activity of the prodigiosin is thought to be attributed to the selective suppression for T lymphocyte activity.
Prodigiosin 25-C, an immunosuppressive analogous to, but different from prodigiosin in structure and molecular weight, is known to suppress the proliferation of T lymphocytes, but not the proliferation of B lymphocytes. Of T lymphocytes, CD8 T lymphocytes are suppressed, but CD4 T lymphocytes are not. In contrast, the prodigiosin of the present invention has an immunosuppressive activity on CD8 T lymphocytes and CD4 T lymphocytes, both. This immunosuppressive activity is similar to those of other preexisting immunosuppressives. Like commercially available immunosuppressives, such as Cyclosporin A, Cyclophosphamide, FK-506 and Rapamycin, the prodigiosin of the invention selectively suppress the immune response of T lymphocytes.
The reaction systems used in the present invention are illustrative of the application of prodigiosin for a basic research of immunology, but not limitative of the use of prodigiosin. The immunosuppressives in current use are needed in various fields. First of all, the treatment of the diseases requiring immunosuppression and the basic research therefor require them. Immunosuppressive drugs are useful to remove the immune response which follows the transplantation of organs or tissues. Another application field of immunosuppressives is a basic research related to immune cells. In this field are included studies on cytokines, activation and differentiation of immune cells, and intracellular signal transduction. Cyclosporin A, Cyclophosphamide, FK-506 and Ripamycin are available for this field. Because the prodigiosin of the present invention has an activity similar to that of the above immunosuppressives, it can be used as a curing agent and a standard in such various fields.
The prodigiosin of the present invention was found to have the following chemical formula with a molecular weight of 323 as measured by NMR. 